A nurse is caring for a client who is diagnosed with a deep vein thrombosis (DVT) and is receiving heparin. The client asks the nurse how long it will take for the heparin to dissolve the clot, which of the following responses should the nurse give?

A. PT/INR is more relevant for monitoring anticoagulant therapy like warfarin, not heparin. B. This response is accurate; heparin prevents further clot formation but does not dissolve existing clots, which can take time for the body to reabsorb. C. Heparin begins to exert its effects quickly, and therapeutic levels are not measured by PT/INR but by aPTT or anti-factor Xa levels. D. Clots do not dissolve immediately after the first dose of heparin; the medication's role is to prevent clot extension.